The present invention is related to the use of a drum dryer for deliquification of acrylonitrile production waste. In particular, the present invention is related to the use of a drum dryer for deliquification of acrylonitrile waste streams produced during the practice of the Sohio Acrylonitrile Process.
The problem of minimization of waste products produced in any chemical processing plant is becoming acute due to environmental as well as disposal problems. In the practice of the Sohio Acrylonitrile Process the production of liquid waste streams containing solid particulate material is a problem because conventional means of disposing of these streams is becoming more and more expensive. Accordingly, minimization of the volume of these streams is desirable. Typically, mechanical dewatering equipment such as a centrifuge or filter have been utilized to deliquify these waste streams to reduce their volume. Solid bearing waste streams from the commercial acrylonitrile plant are typically sent to a primary solid-liquid separation device for an initial phase separation. In this device the solids are concentrated into a slurry stream containing between about 7 to 40 percent solids. This stream is then mechanically dewatered using either a centrifuge or filter press to produce a sludge cake containing between about 30 to 60 percent solids. The liquid recovered during the mechanical separation is recycled back to the primary phase separation device or disposed of directly.
It would be highly desirable to process this sludge cake in a economic and efficient manner to further concentrate the solid material. However, until the present invention the inherent nature of the sludge cake has made further processing uneconomical or impossible.